Safety switch



June 8 1926.

. O. H. VAN AMBURG Er AL SAFETY SWITCH Filed June 25 1923 Their' AttOrhey,

Patented .lune 8, 1926.

UNITED STATES PATENT OFFICE.

OTTO E. VAN AMBURG AND LESLIE A. KEMI'TON, OF BBIDGEPORT, CONNECTICUT,ASSIGNORS T0 GENERAL ELECTRIC COMPANY, A CORPORATION` OF NEW YORK.

SAFETY SWITCH.

Application filed June 25, 1923. Serial No. 647,513.

The present invention relates to electric switches and more especiallyto safetyv switches. When electric power is utilized in industrialestablishments for driving individual machines, it is desirable that theoperator of the machine be enabled to st art and stop it at will byclosing andv opening the electric/circuit. On account of the daner ofserious accidents occurring through ignorance, carelessness or curiosityon the part of an operative in coming in contact with an electricallycharged part, it is customary in such power installations to providesafety switches for use in starting .and stopping the machines. Thecharacteristic feature of these switches is that all the elec tricallycharged parts are locked up in a protective encasement with only theinsulated operating handle accessible on the outside thereof.

The object of our invention is to provide an improved safety switchwhich shall be strong, compact, eiicient in service, capable of standingrough usage, and of low manufacturing cost.

One embodiment of the invention is shown in the accompanying drawing inwhich Fig.

"1 is a front elevation of our safety switch,

with the switch lever in oli position; Fig. 2 is a vertical section ofthe enclosing box with the circuit interruptino means shown `in sideelevation therein; Fig. 3 is a fragmentary view simil-ar to Fig. 1 butwith the switch lever in the on position, and Fig. 4 is a fragmentaryelevation of the locking lugs.

The switch mechanism 1 is of the oscillating snap type with theoperating handle 2 pivoted at 3 and project-ing through a slot in thebox cover. The switch is carried by an insulatingobase plate 4 securedto the bottom of the j x and provided with barriersA 5 between thestationary contacts 6 of the respective circuit phases. Mounted on oneend of the hase plate 4 are thermal cutouts 7 connected to the loadterminals 8 and the adjacent switch contact-s 6.

The enclosing box is drawn up from sheet steel with its rectan larbottom 9 and side and end Walls 10 an 11 integral. The cover 12 is madeflat and has a eripheral ange 13 fitting about the open si e of the boxand is hinged at 14 to the upper end thereof The upper half of the boxis provided witl. a false front or apron 15 which serves to maintainenclosure of the switch mechanism.

1 when the cover 12 is raised to inspect or renew the cutout. This apronis in the form of a substantially fiat plate :and is held in place byscrews 16 engaging lugs on the opposite side walls 10 of the box. A slot17 is formed ,in the apron 15 of a size to permit the shank of theswitch handle 2 to move back and foith freely therein. A combined shieldand locking lever Y18 is pivoted at 19 to theinside of the apron. Theshield end 20 of the lever is made T-shaped so as to always underlie andshield the slot 17 in whichever position it may be moved by the extendsthrough an aperture 22 at the center end 23 of the lever is madeL-shaped with an aperture 24 adjacent the; angle thereof. It extendsthrougha slot 25 in the right hand side of the box adjacent a bracketor'extension 26 secured thereto and having apertures 27 adjacent itsends' with the upper one of which the aperture 24 of the lever 18registers in its extreme off position.

The cover 12 is provided with a bracket 29 corresponding to the bracket26 on the side of the. box and provided with registering apertures 30.When the'pparts are in the positions indicated in Fig. 1, a padlock 31may be entered in the upper apertures of the brackets 26 and 29 and thelocking lever 18 and thereby lock the switch in oil' position and thecover from being raised. By inserting the padlock 31 in the lowerapertures of the brackets 26 and 29, only the cover will be securedagainst movement, while the switch is left free to be opened and closed.

' With the parts in the positions indicated in Fig. 3, the padlock 31cannot be entered in the upper apertures of the brackets 26 and 29because of the bent end of the locking lever 18 being disposed in thepath and in consequence whereof it is impossible to lock the switch inthe on or closed circuit position.

The operating handle 2 is made with a greater diameter than its shank 21and the shoulder 32 at the inner end of the handle is locatedsubstantially lin the plane of the box cover, which has a slot 33corresponding to slot217 in the apron and a relatively large opening 34at the lower end thereof whereby.;- the handle may be enabled to clearthe cover be in the depressed or in the open switch po- A or' the shieldend 20. The outer or locking l sition. Should, however, the handle beraised out of its extreme od position, the sides of the slot 33 willabut the shoulder 32 oi the handle and prevent the lid being raised. f

lin order to render the switch more readily adaptable to stacking instorage and shipping the handle 2 is made disconnectable' .from itsshank and this is accomplished by means of a set screw 35 located in acountersunk hole in the handle and engaging a j tapped hole in the shank2l, and to prevent swiveling of the handle thereon, it is provided atits inner end with a tongue 36 and the shank with a corresponding groove37.

While we have shown and described the best embodiment of the inventionhewn to dit us, we do not desire to be restricted thereto, "What weclaim as new and desire to securel by Letters Patent of the UnitedStates, is

l. A safety switch comprising a pivotal switch mechanism, its contactsand thermal responding tothe slotin said apron and hav# ing am emm'gqd@PQR at one end of 'its assenti slot vto permit passage of the switchoperating means therethrough during opening and closin movements of saidcover.

2. safety switch comprising a switch -having a pivoted operating handle,cutout therefor, an apron fixed to said enclosure over the said switchand provided with a guide slot for said switch handle, a combined slotshield and locking'lever pivoted upon said apron and adapted to engagesaid switch handle at one end and to extend through the side wall ofsaid enclosure at the other, a cover for lthe open side of saidenclosure hinged thereto, padlock extensions on sai cover and saidenclosure opposite the v projecting end of said lever, said lever andsaid extensions having apertures adapted to re ister only when -theswitch is moved into otr position.

ln witness whereof, we have hereunto set our hands this 21st day of dune, 1923.

@'l'l@ H., VAN AMBURG. LlESlJlE A. KETN.

